 Neuropsychological Assessment for
Parkinson's Disease and Movement DisordersNeuropsychology
has a long history of close collaboration with functional neurosurgery.
Traditionally, assessment has been used to establish a baseline of
neuropsychological function prior to surgery, thereby permitting an
evaluation of cognitive change following surgery.
Over the past 10 to 15
years, neuropsychological data have been increasingly used to predict
outcome following elective neurosurgery.
One of the primary goals of functional neurosurgery is to improve the
patient's quality of life. In order to make an informed choice about an
elective neurosurgical procedure, patients and their family members need
to have a clear understanding of the potential surgical benefits and
risks associated with not only the underlying neurological disorder, but
important cognitive and personality variables as well.
Many of the surgical targets
identified for DBS are important components of various complex
fronto-subcortical circuits. These fronto-subcortical circuits are
critical for normal cognitive, mood and personality function, as well as
motor function. Disruption to these circuits, either via the underlying
disease state, medication effects or surgical treatment, can
theoretically impact neuropsychological or neuropsychiatric function
either for the better or worse. Neuropsychological assessment quantifies
these changes and can help improve patient care.
The role of the neuropsychologist on
a DBS team is multifaceted. The preoperative neuropsychological
assessment is used to establish a baseline of neuropsychological
function from which changes following surgery can be assessed. Many
patients who are candidates for DBS have underlying neurodegenerative
disorders. Neuropsychological assessment is key to diagnosing dementia
and identifying other cognitively or psychiatrically vulnerable patients
who might not be able to comply with the demands of surgery and/or
postoperative treatment requirements.
Neuropsychiatric symptoms are common
in many DBS patients. A comprehensive neuropsychological assessment,
with patient and family interviews, is essential in identifying patients
with neurobehavioral problems that might present treatment challenges
(e.g., impulsivity, poor judgment). Preoperative neuropsychological
assessment is useful in identifying patients who might benefit from
referral to psychiatry prior to surgery in order to provide
comprehensive patient care and improve postoperative outcome. The
preoperative neuropsychological interview also provides an opportunity
to assess the family's level of support for the patient's decision to
proceed with surgery as well as the extent to which the patient's and
family members' goals for surgery are realistic. The accurate
assessment of all of these variables (cognitive status, mood and
personality variables, family support, goals for surgery) is essential
to providing optimal patient care.
Information obtained from the
pre-operative neuropsychological assessment is considered in conjunction with the neurosurgical
and neurological findings. The team members use all of this information
to come to a consensus decision regarding the appropriateness of surgery
for every patient and to develop a comprehensive treatment plan.
Follow-up neuropsychological assessment is essential after surgery to
document any changes following the procedure and to provide appropriate
feedback to the patient, family and treating physicians.
Finally, the neuropsychological
assessment of DBS patients provides an exciting opportunity to study
brain-behavior relationships. Well-designed, clinical research trials
with these patients can lead to a better understanding of the underlying
functional neuroanatomy of various cognitive and psychiatric behaviors
and help identify important postoperative outcome predictors.
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